Backup Designated Router: 10.0.12.2 Timers: Hello 1, Dead 40, Poll 120, Retransmit 5, Transmit Delay 1 A. The router ID is 10.1.2.2. B. The interface ID is 1500. C. This router is BDR. D. The…

Question

Options

• AThe router ID is 10.1.2.2.
• BThe interface ID is 1500.
• CThis router is BDR.
• DThe interface IP address is 10.1.12.1.

• A
  6% (1)
• B
  13% (2)
• C
  75% (12)
• D
  6% (1)

Explanation

Option C is correct because the OSPF output explicitly lists the Backup Designated Router IP as 10.0.12.2, and this matches the local router's interface address - meaning the router viewing this output is the BDR on this segment. When a router's own interface IP appears in the BDR field, it holds that role.

Why the distractors are wrong:

• A is wrong because 10.1.2.2 is not derived from any value shown; the BDR IP is 10.0.12.2, and router IDs are separately configured or elected - you cannot infer the router ID just from the BDR IP.
• B is wrong because 1500 is the standard Ethernet MTU (Maximum Transmission Unit), not an OSPF interface ID - the interface ID would be a small integer identifying the logical OSPF interface.
• D is wrong because the interface IP must be 10.0.12.2 (matching the BDR field), not 10.1.12.1.

Memory tip: In OSPF show output, if your router's IP appears in the "Backup Designated Router" line, you are the BDR - OSPF always lists the local router's own address in the DR or BDR field when it holds that election role.

No community discussion yet for this question.